Firstly, a basic structure of a conventional IC handler will be explained. As shown in FIG. 12, in the IC handler 50, an IC, which has been stocked in a container 52 for supplying ICs, is supplied into a socket 56 of an IC checker 54 to execute tests at a normal temperature and at a high temperature. The IC handler 50 automatically sorts and accommodates the ICs checked into containers 58 for sorting ICs. The ICs are conveyed from the container 52 to the socket 56, and from the socket 56 to the containers 58 by conveying means 60 and 62.
By the way, these days ICs are higher integrated to have higher function, so they have many leads. Thus, lead pitch of ICs become finer and finer. By having fine pitch leads, the IC in the socket 56 must be supplied with high positioning accuracy.
To precisely supplying ICs into the socket 56, a method utilizing an image processing technology, which includes the steps of catching images of the conveying means and an IC, which is held by the conveying means, by a camera and processing image data thereof to supply the IC into the socket, is known. But an image processing equipment is expensive, and it takes a long time to process image data so time length for checking an IC must be long.
Then, a conventional IC handler, which has been widely used, will be explained.
A positioning mechanism 64 is provided between the supply container 52 and the socket 56. When an IC is conveyed from the container 52 to the socket 56, the IC is once positioned to supply into he socket 56. Then the IC, which has been positioned, is conveyed to and mounted onto the socket 56 by transferring means 66.
The positioning mechanism 64 of the IC handler 50, which once positions the IC before supplying the same to the socket 56, will be explained with reference to FIGS. 13-16.
The positioning mechanism 64 has following structure. The IC 70 is mounted on an upper face of a rectangular table 68.
A positioning wall piece 72 is provided to enclose the rectangular table 68, and lower portions S of two pairs of inner faces 74, 76 and 78, 80 thereof are formed into vertical faces 82, each pair of which are mutually faced and separated with a distance corresponding to outermost edges of the IC 70. On the other hand, upper portions T of each pair of the inner faces are mutually faced and formed into slope faces 84 whose distance is gradually made longer upward. Note that, there are designed clearance, whose size is designed within predetermined allowable error, between the outermost edges of the IC 70 and the vertical faces 82 of the lower portions S.
A vertical mechanism 86 includes an actuator, e.g., an air cylinder. The vertical mechanism 86 moves the table 68 in the vertical direction with respect to the positioning wall piece 72.
A conveying means 60 is capable of three-dimensionally conveying the IC 70. The conveying means 60 is capable of horizontally conveying the IC 70 to a position above the table 68. Further, the conveying means 60 is capable of moving downward to mount the IC 70 onto the upper face of the table 68. The conveying means 60 has a sucking pad 88. The IC 70 is held by the sucking pad 88.
A transferring means 66 is capable of conveying the IC 70, which has been positioned on the table 68, to a socket 56 for tests. The transferring means 66 is capable of three-dimensionally moving, and it has a sucking pad 88 for holding the IC 70 as well as the conveying means 60. Note that, the conveying means 60 may act as the transferring means 66.
Next, action of the IC handler 50 will be explained. Note that, the conveying means 60 and 62, the transferring means 66, the vertical mechanism 86 and the checker 54 are controlled by a controller, not shown, on the basis of a predetermined program.
Firstly, the table 68 is moved upward, by the vertical mechanism 86, until the upper face corresponds to the upper portions T of the inner faces 74-80 of the positioning wall piece 72.
In this state, the IC 70 is conveyed to and mounted onto the upper face of the table 68 by the conveying means 60 as shown in FIG. 13. Then the vertical mechanism 86 moves the table 68 downward until the upper face corresponds to the lower portions S of the inner faces 74-80 of the positioning wall piece 72 as shown in FIG. 14.
For example, the IC 70 is deviated distance A, leftward, with respect to the vertical face 82 of the positioning wall piece 72, as shown in FIG. 13, when the IC 70 is mounted onto the upper face of the table 68. In this case, leads 90, which constitute the outermost edge of the IC 70, come into contact with the slope face 84 of the positioning wall piece 72 with the downward movement of the table 68, so that IC 70 is horizontally moved rightward, in FIG. 13, and finally positioned between the vertical faces 82 of the positioning wall piece 72 as shown in FIG. 14.
Upon completing the positioning of the IC 70, the vertical mechanism 86 moves the table 68 upward until reaching the initial position, as shown in FIG. 15, and stops the same there. In this state, the conveying means 60 is capable of sucking the IC 70, which has been positioned on the table 68.